What method is used to dispense influent over the media in intermittent sand filters?

The method of timed dosing with pump chambers is effective in controlling the flow of influent over the media in intermittent sand filters. This approach allows for a regulated and precise amount of wastewater to be distributed at set intervals, which is crucial for ensuring optimal treatment. Timed dosing enables each dose to saturate the media adequately and allows time for aeration and treatment, as the media is not continuously flooded. This intermittent wetting and drying cycle is essential for maintaining the performance of the sand filter by promoting aerobic conditions and preventing clogging.

In contrast, the other methods are less advantageous: manual distribution may lead to inconsistent application and is labor-intensive; continuous flow from a reservoir can result in oversaturation and reduced treatment efficiency; and gravity discharge without timing may overwhelm the system, leading to hydraulic loading issues.